Human hair has been brushed using brushes of various shapes and with a variety of bristles to shape, fashion and groom the hair since the beginning of time. In more recent times, hair grooming procedures have included adding fixatives to the hair and then employing devices useful in curling hair which tended to be straight, and or straightening hair which when left on its own tended to be curly. This application is extremely important to either of the above operations.
Before proceeding further, it is important to understand some of the important characteristics of human hair and terms that will be used throughout this disclosure.
It is well known that the physical characteristics of human hair change significantly with changes in the surrounding humidity. Human hair has long been used as the driving element in mechanical humidity gauges because of its extreme sensitivity to small changes in humidity.
In certain instances, the characteristics of human hair may be best understood by an analogy with spaghetti strings. When purchased by a consumer, spaghetti is most inelastic and of a set length. Upon immersion in water, the spaghetti will stretch significantly and if while in this state, the pliable spaghetti is wound around a collapsible mandrel and the pliable spaghetti is heated by some means when sufficient moisture is removed from the spaghetti and the previously pliable spaghetti is elevated to a predetermined temperature, the spaghetti may now be cooled and the mandrel on which it was wound, now collapsed and removed. The spaghetti will retain its "curled" configuration.
In a similar manner, curly hair may be curled and/or straightened. It is only a matter of combining moisture, fixatives, etc., heat and cooling to the hair to take advantage of the human hair's natural characteristics to obtain the desired "set" or other desirable grooming results.
An experienced professional hair designer will instinctively possess the "time recognition" required to know how and when to take advantage of these natural physical characteristics to obtain the desired styling result.
For instance, if a client is seeking a hairstyle which involves curling the hair, the experienced designer will begin with a client whose hair has been washed, properly conditioned, and to which the desired fixatives may have been applied, and whilst still wet selected locks of the wet hair are wound around a selected bristle brush and the hair so wound around the brush is heated to a temperature of between about 100.degree.-110.degree. F. by blowing hot air on the hair and brush until the designer instinctively recognizes that this temperature has been reached. During this period of time, the hair has decreased in length and begun its "set". The designer now begins to blow cold air on the hair and the brush to lower the temperature of the hair, and any fixatives applied to the hair (and the brush) to a temperature of about room temperature to complete the "set".
Similarly, to "straighten" what is generally referred to as naturally curly hair, the designer will choose a high density bristle brush, and taking a curl of hair previously washed and conditioned, and to which a suitable fixative may have been applied, wrap the curly hair (whilst still wet) around the high density brush and heat the hair and brush around which the hair is wound to about 150.degree.-160.degree. F. by blowing hot air from a hair dryer onto the hair and brush. The experienced hair designer will now begin to unroll the hair from the brush and while maintaining some tension on the hair with the high density brush, apply a cold stream of air to the hair as it just leaves the hot brush. This cold air completes the "set" and the previously curly hair will emerge from the process by now being straight. The hair emerges from the hot brush and is cooled as it emerges from the roll of bristles on the brush.
The experienced hair designer must be able to gauge the temperature of the hair (and the brush on which it is wound) from past experience to be able to consistently obtain the "best" results for the client. Years of experience are usually required to provide the necessary "time recognition" required to produce the desired result. The importance of cooling the hair to improve the "set" cannot be overstressed.